On Sat, Feb 02, 2008 at 03:39:08PM +1100, [EMAIL PROTECTED] wrote: > Hello, > > I have been looking at the wiki version of the network reference > [ http://wiki.debian.org/DebianReference/Network ] > > I have a few questions about the description of "allow-hotplug", which > I think could be improved further. I have always found the documentation > for this stanza difficult to understand, both in the Reference and in > interfaces(5). > > Question 1. > In the table of stanzas, you have this line > | "allow-hotplug <interface_name>" | > To start interface <interface_name> upon hotplug event of the system. | > > I take this to mean that there is hotplug support in the ifupdown > programs, so that they can respond to hotplug events from the kernel. > Is that correct? > Would it be better to say it this way? > | "allow-hotplug <interface_name>" | > Start interface <interface_name> when the kernel detects a hotplug event > from the interface. |
Yes. If you think this table should use imperative than noun pharase, please correct all. For now, I kept "To verb ..." structure. Done for now. > Question 2. > Under "The network interface served by the DHCP" is the sentence: > The following configuration entry in the /e/n/i file brings up the > primary network interface eth0 upon the Linux kernel finding up the > physical interface eth0 (via allow-hotplug stanza) while configuring > it with DHCP. > > Would it be better to say this? > The following configuration entry in the /e/n/i file is the typical > way to set up a network interface in such an environment. When the > Linux kernel detects the physical interface eth0, the allow-hotplug > stanza will cause ifup to bring up the interface and the iface stanza > will cause ifup to use DHCP to configure the interface. Yes. Much more readable English. Done. > Question 3. > > If I understand correctly the "hotplug events" referred to here are > relating to the network hardware being hotplugged into a running system, > eg a PCMCIA card being inserted or a USB ethernet device being plugged in. > > When a system with a built-in ethernet card is powered up, is a hotplug > event generated when the kernel detects it, during the boot sequence? That should only be enabled by "auto", I thought. > Question 4. > If I power up a system with a built-in ethernet interface, but with > no ethernet cable plugged into it, does plugging in an ethernet cable > also generate a hotplug event that is noticed by allow-hotplug? Unfortunately no at this moment. I should say I was annoyed for this when I forget to plug in wire. I always have to do "ifdown eth0; ifup etho". It becomes some zombee state as I observed. This is very good question. > This last part is the piece I find most confusing. The section on the > wiki page about "The caution for operations" helped quite a bit, > explaining that if one is using ifplugd then "auto" and "allow-hotplug" > should not be used. I think that is the first time I have seen that > written down clearly. I inherited that from the previous version mostly described by Thomas Hood. If you understand that these system has layered structure, it is quite natural. > The section "auto-switchable network configuration" hints that the > answer here is yes, plugging in an ethernet cable generates a hotplug > event that allow-hotplug will act upon. > If so, does that mean ifplugd is no longer needed? Tat is what it is. But am not in such fancy network now to positively test it. I just summarized documentation here. In the second thought, if unplugged ethernet cause funny network state, how can it be done like this. I may be wrong here. Recently, I put ifupdown-extra package into my system. Which seem to do something on unplugged ethernet cable.... I need to check... Let me do ifdown / unplug / ... and: [EMAIL PROTECTED]:~$ sudo ifdown eth0 Restarting mail retriever agent: fetchmail. There is already a pid file /var/run/dhclient.eth0.pid with pid 4110 killed old client process, removed PID file Internet Systems Consortium DHCP Client V3.1.0 Copyright 2004-2007 Internet Systems Consortium. All rights reserved. For info, please visit http://www.isc.org/sw/dhcp/ Listening on LPF/eth0/00:19:e3:63:0e:3f Sending on LPF/eth0/00:19:e3:63:0e:3f Sending on Socket/fallback option_space_encapsulate: option space agent does not exist, but is configured. DHCPRELEASE on eth0 to 192.168.11.1 port 67 [EMAIL PROTECTED]:~$ sudo ifup eth0 osamu[12616]: WARNING: Initialising interface eth0 which does not have link Internet Systems Consortium DHCP Client V3.1.0 Copyright 2004-2007 Internet Systems Consortium. All rights reserved. For info, please visit http://www.isc.org/sw/dhcp/ Listening on LPF/eth0/00:19:e3:63:0e:3f Sending on LPF/eth0/00:19:e3:63:0e:3f Sending on Socket/fallback option_space_encapsulate: option space agent does not exist, but is configured. DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 9 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 13 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 12 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 9 DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6 No DHCPOFFERS received. No working leases in persistent database - sleeping. [EMAIL PROTECTED]:~$ ifconfig eth0 Link encap:Ethernet HWaddr 00:19:e3:63:0e:3f UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:296268 errors:0 dropped:0 overruns:0 frame:0 TX packets:208408 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:324564384 (309.5 MiB) TX bytes:75106855 (71.6 MiB) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:13564 errors:0 dropped:0 overruns:0 frame:0 TX packets:13564 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2849107 (2.7 MiB) TX bytes:2849107 (2.7 MiB) [EMAIL PROTECTED]:~$ This "Link encap:Ethernet" is the state without wire. Let me plug-in: Nothing happen. then I run ifdown/ifup eth0 Link encap:Ethernet HWaddr 00:19:e3:63:0e:3f inet addr:192.168.11.2 Bcast:192.168.11.255 Mask:255.255.255.0 inet6 addr: fe80::219:e3ff:fe63:e3f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:296348 errors:0 dropped:0 overruns:0 frame:0 TX packets:208538 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:324579278 (309.5 MiB) TX bytes:75124347 (71.6 MiB) Interrupt:16 Oh, I am using simple single DHCP set up now. At least, plugging-in wire does not cause hotplug event. I need to check how ifupdown-extra can be leveraged. Any onw with idea? > Question 5. > At the top of the page it explains: > This section will address network setup for the mobile PC which moves > around different networks. (For the non-mobile PC, the debian-installer > should have taken care your network setup and there are almost nothing > for us to play with.) > I think that it would be worth including a short subsection describing > how a non-mobile PC is normally set up. What do others think? > For example: > > == Non-mobile PCs == > Systems that are normally permanently attached to a single network > should have been correctly configured by the debian-installer. > Typically the /e/n/i file looks like this: > {{{ > auto lo > iface lo inet loopback > auto eth0 > iface etho inet dhcp > }}} > In some cases the host may have a static IP configuration for eth0, > like that shown in "The network interface with static IP". > > Non-mobile systems typically do not need the {{{resolvconf}}} package; > their name resolution can be set up via DHCP or by manual editing of > {{{/etc/resolv.conf}}}. This is generally true. How about PC directly on PPPoE or PPP dial-up. The above is good onlt for PC behind router or some DHCP serverd network. > Yes, this is a bit redundant but I think it might help readers looking > for authoritative information on setting up their LAN machines. If you can think of non-redundant way, I will follow you. Osamu -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]